Solar heat pump

ABSTRACT

A heat transfer system combining a solar collector and a vapor jet compressor pump. The solar collector provides two streams of heated vapor, one at a relatively high temperature and one at a relatively low temperature. The high temperature vapor provides the motive vapor for the vapor jet compressor pump. The vapor jet compressor pump entrains the lower temperature vapor and acts as a heat pump effectively pumping its temperature to a higher temperature useful for space heating. The solar energy supply may be supplemented by an auxiliary convention energy source and the vapor jet compressor pump may be supplemented by a self-energized circulation pump.

RELATED APPLICATIONS

This application is divisional of application Ser. No. 07/319,281 filedMar. 06,1989 now U.S. Pat. No. 5142882 which is a continuation in partof applicant's Ser. No. 611,197 filed May 17, 1984 and expected to beissued Mar. 7, 1989 as U.S. Pat. No. 4,809,523, entitled Thermal Coolingand Heat Transfer System. The specification of Ser. No. 611,197 isincorporated herein by reference.

BACKGROUND OF THE INVENTION

This invention pertains to an apparatus and method for collecting solarenergy and using it to heat or cool space. More particularly, thisinvention pertains to a solar heat pump that collects at lowtemperatures solar heat that would be lost by conventional collectorsand increases the temperature thereof, by means of a heat pump, so as torender it useful for space heating. This invention also relates to theuse of a vapor jet compressor pump as a heat pump in conjunction with athermal barrier solar collector.

U.S. Pat. No. 4,809,523 describes art relating to the heating or coolingof a heat transfer medium involving vaporization of a portion of thefluid.

OBJECTS OF THE INVENTION

It is an object of the present invention to provide a combination of asolar collector and a vapor jet compressor pump that together have acapability for nearly 100% thermal collection efficiency.

It is another object of the present invention to provide a collectorthat when operated in conjunction with a vapor jet compressor pump andan auxiliary energy supply can provide thermal energy-for usefulpurposes when competing collectors are useless because the temperaturesare too low for useful heating of space.

It is another object of the present invention to provide a solar energysystem that needs no storage capability because it can work equally wellwith an auxiliary fuel supplying energy to the system.

It is an object of the present invention to provide a combined solar andauxiliary energy system which provides reliable 24 hour operationirrespective of weather conditions.

It is an object of the present invention to provide a solar energysystem that makes use of solar energy at collected temperatures as lowas 40 F. when an auxiliary energy supply is used.

It is an object of the present invention to provide a solar energysystem that can operate in the self-energized mode in the advent of apower failure.

It is an object of the present invention to provide a solar energysystem that supplies both heating and cooling of space.

SUMMARY OF THE INVENTION

The present invention is directed to the combination of a vapor jetcompressor pump which acts both as a heat pump and as a heat transferfluid pump simultaneously, and a thermal barrier solar collector whichcollects solar energy at a high temperature for providing motive steamfor the vapor jet compressor pump and collects solar energy at a lowtemperature for providing a supply of low pressure vapor for the heatpump. High temperature vapor from the thermal barrier solar collectormotivates the vapor jet compressor pump which in turn pumps heat fromthe lower temperature thermal barrier of the solar collector. Thecombined motive and barrier heat from the thermal barrier solarcollector heats the heat transfer medium being circulated by the vaporjet compressor pump to provide useful heat for space heating. Thecombination provides a self-energized system for the heating and coolingof space.

The invention is further directed to a heat transfer apparatus whichincludes a first vapor jet compressor pump having a motive vapor inlet,a feed liquid inlet, a low pressure vapor inlet and a discharge outlet;a second vapor jet compressor pump also having a motive vapor inlet, afeed liquid inlet, a low pressure vapor inlet and a discharge outlet;means, such as the thermal barrier solar collector, for providing afirst source of heated vapor at a relatively high temperature and asecond source of heated vapor at a relatively low temperature; operativeconnection of the motive vapor inlets of the first and second vapor jetcompressor pumps to the first source of heated vapor; operativeconnection of the discharge outlet of the first vapor jet compressorpump to the feed water inlet of the second vapor jet compressor pump;operative connection of the low pressure vapor inlets of at least one ofthe vapor jet compressor pumps to the second source of heated vapor; andoperative connection of the discharge outlet of the second vapor jetcompressor pump a heat transfer loop including to the feed water inletof the first vapor jet compressor pump.

According to another embodiment of the invention, an auxiliary heatsource is operatively connected to the motive vapor inlet of the firstvapor jet compressor pump.

Pursuant to a feature of the present invention, the thermal barriersolar collector comprises a cover glass plate, a thermal loss barrier, alouvered plate, and an absorber plate. The thermal loss barriercomprises two plates enclosing a thin layer of heat transfer fluid andacts as a barrier to heat loss through convection and radiation from thehigh temperature absorber plate. The plates may be made of materialsother than glass that are transparent to solar radiation. Evaporatortubes disposed with the thermal barrier absorb this heat that wouldotherwise be lost and provide low pressure, low temperature vapor forthe low pressure vapor inlet of a heat pump, such as a vapor jetcompressor pump.

Pursuant to a further feature of the present invention, the thermalbarrier solar collector is combined with two vapor jet compressor pumps.The first vapor jet compressor pump is motivated by the heated vaporfrom the collector's absorber plate and acts to boost the feedwater flowthrough the second vapor jet compressor pump. The second pump acts as aheat pump for the vapor in the thermal barrier section of the collector.

Pursuant to another embodiment of the invention, a single vapor jetcompressor pump with dual, e.g., concentric, steam inlet nozzles isutilized. The outer annular nozzle preferably is charged by aconventional auxiliary steam generator while the inner nozzle is chargedy the heated vapor from the absorber plate of the thermal barrier solarcollector. Alternatively, these connections may be reversed.

Pursuant to another embodiment of the present invention, a separatelyenergized circulation pump is utilized to increase flow through thevapor jet compressor pump and thus improve start-up of the system andavoid any instability problems.

The invention is also directed to a method for using solar energy toheat space, comprising the steps of collecting solar energy in ahigh-temperature vapor and a low-temperature vapor; expanding thehigh-temperature vapor in a vapor jet compressor pump disposed within adischarge heat exchanger's heat transfer loop; compressing andcondensing the low-temperature vapor in a vapor jet compressor pump; andpassing the vapor jet compressor pump discharge through the dischargeheat exchanger.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a diagram schematically illustrating an embodiment of thethermal barrier solar collector of the present invention.

FIG. 2 is a diagram schematically illustrating the dual vapor jetcompressor pump embodiment of the present invention, with valvepositions (a) signifying a heating mode and valve positions (b)signifying a cooling mode.

FIG. 3 is a diagram schematically illustrating the single vapor jetcompressor pump embodiment of the present invention, with valvepositions (a) signifying a heating mode and valve positions (b)signifying a cooling mode.

FIG. 4 is a partial cross sectional view of an embodiment of the nozzles-of the vapor jet compressor pump of FIG. 3.

DETAILED DESCRIPTION

FIG. 1 depicts a flat plate collector 1 which is modified for use with avapor jet compressor pump system. Solar radiation Q_(o) enters throughthe cover glass 2, passes through a thermal barrier 3, then on through alouvered glass plate 8 to a typical black absorber plate 9. The solarradiation is converted into thermal energy by the absorber plate 9 and afraction of this energy is removed by heat transfer medium circulatingthrough heat transfer tubes 10 attached to the plate 9. The remainingfraction of the thermal energy is transmitted back to the louvered plate8 by means of convection and radiation. Glass is normally opaque tothermal radiation hence the louvered plate 8 absorbs both the convectedand radiated thermal energy. The thermal energy received by the louveredplate 8 is in turn radiated and convected to the colder thermal lossbarrier plate 3 which absorbs a portion of the energy and transmits theremainder to the colder cover glass 2. The thermal energy absorbed bythe fluid 7 in the barrier 3 is removed by evaporation of the heattransfer medium in the enclosed tubes 6 that are connected to the lowpressure side of a vapor jet compressor pump or other heat pump. Thevapor is compressed by the vapor jet compressor pump and delivered by itat a higher temperature suitable for effecting heat transfer for heatingspace. The vapor produced by the barrier 3 is shown as the supply to thelow pressure inlet to the vapor jet compressor pump at the top of FIG.2.

A portion of the incident solar radiation is absorbed by the thin layerof clear fluid 7 between the glass covers 4 and 5 of the barrier 3.However, the index of refraction of the fluid, for instance water,nearly matches that of the glass so as to about eliminate reflectionlosses at the liquid-glass interfaces. The transmitted solar energy istherefore about equivalent to that passing through a single pane ofglass. The evaporator tubes 6 in the barrier 3 have a highly reflectivecoating 11 on the upper side so as to reflect solar radiation on downinto the collector 1. The tubes 6 are also shaped so as to minimizesolar-to-thermal energy conversion.

The louvered glass plate 8 above the absorber plate 9 can be positionedso as to adjust its thermal resistance since it may be necessary to varythe heat being transmitted from the absorber plate in order to achieveoptimal performance. The louvers may be operated automatically by meansof a bi-metallic spring device (not shown) such as conventionally usedfor such purposes.

Except for the top cover glass 2, the entire assembly is surrounded bythermal insulation (not shown). Assuming that the heat loss through thisinsulation is comparatively negligible to that through the cover glass2, it becomes apparent that the only loss from the collector 1 is fromreflected solar energy, Q_(ref) and the convection and radiation lossesQ_(c) and Q_(r) from the cover plate 2. Radiation and convection lossesare small compared to conventional flat plate design because the sourceof the losses is the low temperature thermal barrier 3 instead of thehot absorber plate 9 of typical collectors.

When the motive steam, Q_(s), is not sufficient for pumping all the heatgenerated in the barrier 3, either the louver is closed so as toincrease Q_(s) or decrease the amount of energy absorbed by the heattransfer medium in the tubes 6, Q_(e), or an auxiliary supply of steamis used to provide an additional supply to the vapor jet compressor pumpfor pumping, as described below, all the heat generated in the barrier3. Therefore, all the heat collected is used for heating space.

Some of the incident solar radiation is absorbed by the glass 2, 4 and5. A portion of this radiation heats the glass and is ultimatelyabsorbed by the barrier 3. The unconverted reflected radiation, Q_(ref)escapes from the collector 1. The barrier 3 operates at low temperaturesand pressure, therefore less costly plastic having internal mouldedcoolant channels can be substituted for the glass and metal coolantchannels.

The thermal barrier 3 intercepts a large fraction or all of the normalheat loss flow to the outside environment. This heat loss is capturedand then increased in temperature by means of a heat pump so as to beuseful for space heating. The thermal barrier acts as a low pressureheat source and a source of heated vapor at a relatively lowtemperature. The remainder of the solar heat that is not lost to theoutside is normally at the useful higher temperatures of conventionalflat plate solar collectors and is used for separate energy demands.

The collector 1 accordingly supplies energy at two different temperaturelevels. The energy supplied at the higher level of temperature is usedto motivate a heat pump to raise the temperature of the energy suppliedat the lower temperature so as to deliver both energy supplies at atemperature level useful for space heating. The heat pump action may beprovided by the vapor jet compressor pump. The efficiency of solar heatcollection resulting from collection of the heat at two differenttemperature levels and raising the average temperature to useful levelsis expected to be more than twice that of conventional solar heatcollectors.

Two vapor jet compressor pump concepts for heating and cooling space aredescribed which use an auxiliary heat source, such as natural gas orfuel oil, and a solar supply of thermal energy. The two energy sourcesare used either separately or in parallel depending on the availabilityof solar energy. The combination of these heat sources ensures theheating or cooling of space on demand and yet utilizing 70% or more ofthe total solar radiation that enters the cover plate 2.

The '523 patent specification, incorporated herein, describes the basicoperating principles of vapor jet compressor pump heating and coolingsystems energized by a single thermal source of energy such as fromsolar radiation. This section presents two concepts of the vapor jetcompressor pump system using solar radiation and/or conventional fossilfuel heat sources in combination or separately so as to ensure heatingand cooling at all times on demand.

FIG. 2 is a schematic diagram of the dual vapor jet compressor pumpHeating System showing valves in position (a) for the space heating modeof operation. The alternate valve position (b) converts the system intothe space cooling mode.

A first vapor jet compressor pump 12 has its motive vapor inletconnected to the absorber plate 9 of the thermal barrier solar collector1 by means of steam separator 20; its low pressure vapor inlet connectedto either the thermal barrier 3 of the collector 1 by means of steamseparator 19 and valve Y or to the evaporator (not shown) by means ofvalve Y. Discharge heat exchanger 15 provides cooled heat transfer fluidmedium, such as feedwater, to the first vapor jet compressor pump 12.Pump 12 discharges into the feed liquid inlet of the second vapor jetcompressor pump 13 by means of a thermostat control 16.

The second vapor jet compressor pump 13 has its motive vapor inletconnected to either the absorber plate 9 by means of steam separator 20and check valve G or to an auxiliary source of steam 28. The auxiliarysource of steam 28 can be any non-solar source, for fuel oil or naturalgas source. When it is cycled on by conventional controls, steamgenerator 28 supplies motive steam for vapor jet compressor pump 13.

A step-by-step description of the system's operation follows for thesolar only case; for operation with solar and conventional heat sourcesin parallel; and for operation solely energized by conventional energysources such as gas or fuel oil. The system descriptions assumeoperation in conjuction with solar collector 1 shown on FIG. 1, howeverthe self-aligning collector 1 of applicant's U.S. Pat. No. 4,809,523also applies.

The solar-energy only mode of operation is as follows:

(a) solar radiation heats collector 1's barrier 3 and absorber plate 9;

(b) first vapor jet compressor pump 12 and second vapor jet compressorpump 13 are activated and perform in accordance with the operationdescribed in U.S. Pat. No. 4,809,523;

(c) vapor jet compressor pump 12 discharges into vapor jet compressorpump 13 which boosts the flow through the heat exchanger 15;

(d) cooled feedwater returns to vapor jet compressor pump 12 to completethe cycle;

(e) level control valves C and D operate as required in order tomaintain liquid levels in the collector 1.

Operation of the solar collector and the auxiliary steam generatorsupply in parallel is as follows:

(a) there is a demand for heat that the solar enegy supply cannot alonesatisfy;

(b) conventional heating system thermostat and controls initiatecombustion of fuel to heat the steam generator;

(c) steam generator pressure increases causing check valve G to shut;

(d) vapor jet compressor pump 13 is motivated by vapor from steamgenerator 28 and compresses vapor from barrier 3 to remove heat from it.The high pressure steam from the steam generator incidentally 28 maycool barrier 3 to low temperatures increasing the efficiency of thesolar collector 1;

(e) vapor jet compressor pump 13 pumps the heated heat transfer fluid(e.g., water) through the discharge heat exchanger 15 and the cooledwater enters vapor jet compressor pump 12;

(f) motive vapor from the absorber plate 9 of the collector 1 activatesvapor jet compressor pump 12 boosting flow to vapor jet compressor pump13. Flow of steam from the absorber plate 9 continues until itstemperature is the same as the feed water because of the venturi effectof the flow produced by vapor jet compressor pump 13, therefore both thebarrier 3 and absorber plate 9 in this instance become low temperatureheat sources to supply the vapor jet compressor pump 13 heat pumpingaction;

(g) if solar radiation intensity increases, the motive steam from theabsorber plate 9 supports the flow and heat production in parallel withthe auxiliary supply 28;

(h) if solar energy alone can satisfy the heat demand, the auxiliarysupply 28 shuts down as a result of thermostat 16 action;

(i) if the demand for all heating ends, the excess solar heat can beeither dumped through valve X into the outside heat exchanger 14 usedfor rejecting heat during the cooling mode of operation, or it can bestored for instance, in a hot water tank (not shown) using conventionalcontrols for this purpose;

(j) level control valves C and D operate as required to maintain liquidlevels in the collector 1;

(k) level control valve F opens when the level in the steam generator 28is low so as to supply motive steam to the injector 17 which chargesfeedwater into the high pressure steam generator 28. Valve B relievesaccidental overpressure.

In the auxiliary steam supply only mode of operation, steps (a) to (f)immediately above govern.

In an alternative embodiment, the heat storage means, such as a watertank, is operatively connected to the low pressure vapor inlet of one ormore vapor jet compressor pumps whereby the solar energy stored thereinmay be converted to high temperature energy useful for space heatingeven at water tank temperatures as low as about 40 F. In other words,the heat storage means is substituted for the thermal barrier of thesolar collector as the source of low temperature heat. Thus, the steamgenerator 28 and vapor jet compressor pumps combine to allow a greaterpercentage of the storage means' heat capacity to be used for spaceheating. As a result, for example, a smaller storage tank may be used.

The dual vapor jet compressor pump cooling cycle is now described. Forcooling, valves X, Y and Z are turned to the (b) position so as toisolate the barrier 3 in the collector 1 and pump vapor from anevaporator (not shown) located inside the space to be cooled. Valvepositions (b) are indicated on the schematic diagram, FIG. 2, for thecooling mode of operation. In this mode, the suction produced by thevapor jet compressor pumps 12 and 13 are connected to the evaporator(not shown) which provides the required cooling of space. The thermalbarrier 3 in the collector 1 is not connected to the vapor jetcompressor pumps 12 and 13 directly.

By means of valves (not shown) the discharge heat exchanger 15 can beconverted into an evaporator. The heat absorbed by the evaporator isdischarged by the outside heat exchanger 14 that is connected to thesystem when valve X is turned to the (b) position.

The system can be modified to reflect a 3-stage concept in which duringhot summer weather when there is a demand for cooling of space, thebarrier 3 temperature can be permitted to rise sufficiently forgenerating useful motive steam at, for instance, 170 F. or more tosupplement the steam from the absorber plate 9.

The single vapor jet compressor pump heating system of FIG. 3 is nowdescribed. FIG. 3 is a schematic diagram of a dual nozzle vapor jetcompressor pump system, which in one embodiment includes concentricsteam nozzle 23 shown enlarged on FIG. 4. The dual concentric nozzle 23eliminates the need for vapor jet compressor pump 12 shown on FIG. 2. Apop-valve A, which opens at a pre-set pressure, is also added to themotive steam line between the steam generator 28 and the dual steamnozzle 23. The pop-valve A is introduced as a means for overcoming anystart-up uncertainty, if such becomes a problem.

When the pop-valve A is opened, steam from the steam generator 28preferably jets from the outer, annular nozzle 24. The center nozzle 25is connected to the absorber plate 9 steam source. Normally the annularjet will have the highest velocity since the steam generator 28 operatesat high pressures compared to those produced in the solar collector 1.The high velocity steam generator 28 jet will therefore entrain steamfrom the absorber plate 9. Similarly, the outside surface of the steamgenerator 28 jet will entrain vapor from the barrier 3. This nozzleconfiguration 23 causes the motive steam from the absorber plate 9 tocontribute to vapor jet compressor pump action at all absorber steamtemperatures above that of the mixture of feedwater and condensate inthe combining tube of the vapor jet compressor pump 22. At absorberplate 9 steam temperatures less than that of the combining tube mixture,the vapor jet compressor pump 22 is motivated solely by steam from thesteam generator 28 and the steam from the absorber plate 9 is compressedby entrainment and delivered to the combining tube for condensation.Hence, the collector 1 will continue to contribute heat until itsbarrier 3 and absorber plate 9 temperatures approach the freezing pointof the heat transfer medium. This attribute of the system insuresefficient utilization of all available direct and diffuse solar energyincluding albido from the surroundings. A step-by step description ofsystem operation follows for the single vapor jet compressor pump dualnozzle heating system:

(a) space heating is desired and thermostat (not shown) is set so as todemand heat;

(b) conventional controls (not shown) start fuel combustion and heatingof the steam generator 28;

(c) steam generator 28 pressure increases causing check valve E toclose;

(d) pop-valve A opens at a pre-set pressure and motive steam from thesteam generator 28 impacts cold vapor jet compressor pump and feedwaterto initiate flow of water in system;

(e) the motive steam from the steam generator 28 starts flow of motivesteam from the absorber plate 9 by initially entraining it;

(f) if solar energy from the absorber plate 9 and barrier 3 aresufficient for heating, the thermostat shuts down the auxiliary steamgenerator 28 supply;

(g) if the solar heat is in excess, the heat will be automaticallydumped outside or stored as described above;

(h) if the solar energy can not entirely satisfy space heatingrequirements, the steam generator 28 controls will cycle the steamgenerator 28 as required for satisfying the heating demand. The highpressure steam from the steam generator 28 will continue to withdrawsteam from the absorber plate 9 and the barrier 3 by the entrainmentprocess;

(i) level control valves C and D operate as required in order tomaintain required liquid levels in the collector 1;

(j) level control valve F opens when the level in the steam generator 28is low. Valve F connects the steam generator 28 steam supply to aninjector 17 which charges water into the high pressure steam generator28. Check valve E and the steam nozzle 23 isolate the remainder of thesystem from steam generator 28 pressure.

The single vapor jet compressor pump dual nozzle cooling system operatesthe same as for the dual vapor jet compressor pump cooling systemdescribed above.

It has been a design objective to make the vapor jet compressor pumpsystem entirely self energized and independent of outside sources ofenergy such as electrical power so that it can be used in undevelopedareas where neither electrical power or operative and maintenance skillsare available. However the instability of vapor-jet vacuum pumps, asconventionally used, is well known and it limits operation to arelatively narrow band of pressure and temperatures compared to othermethods of refrigeration. The vapor jet compressor pump system is alsosubject to the same limitations. If indeed start-up and instability areshown to be a problem during subsequent development efforts, theself-energized requirement may be waived and a small electrically drivencirculating pump, for instance, can be included in parallel with thefeed water supply to the vapor jet compressor pump so as to force waterthrough it at start-up or at the approach to instability.

A separately energized circulation pump 27 may be activated by anindependent (electrical) source. The separately energized circulationpump 27 causes valve G to close to prevent recirculation around the pump27. The pump 27 also operates in series with the vapor jet compressorpump hence is relieved of the fraction of the circulation load. Whenoperating at design conditions, the vapor jet compressor pump 22provides ample pumping power hence appropriate controls discontinue useof the separately excited pump 27 and check valve G automatically opensto permit the vapor jet compressor pump to provide all the energyrequired for circulation.

In the case in which the auxiliary energy supply 27 is not activated,the nozzle arrangement simply reduces the pressure in the auxiliaryenergy supply line to pop valve A. The check valve G opens so that theself-energized flow produced by the vapor jet compressor pump 22by-passes the separately energized circulation pump 27 which is notoperating in this mode of operation.

The combination of the thermal barrier solar collector 1, auxiliaryenergy supply 28 and the vapor jet compressor pump 22 is brought intooperation by means of suitable controls when available solar energy isnot adequate for supplying the heating or cooling requirements.

In the heating mode, vapor is generated in either the auxiliary supply28 or the motive steam generator 9 of the thermal barrier solarcollector 1 or both in parallel to motivate the vapor jet compressorpump 22. The vapor jet compressor pump 22 in turn pumps heat from thethermal barrier 3 of the solar collector 1. The vapor condenses in thevapor jet compressor pump, provides vapor jet compressor pump 22 pumpingenergy, and heats the heat transfer medium which discharges from thevapor jet compressor pump and by-passes the non-operating circulationpump 27 to discharge useful heat into the discharge heat exchanger 15.The cooled heat transfer medium returns to the vapor jet compressor pump22 to complete the cycle. The valve positions for the cooling mode areindicated as (b) on the schematic diagram of FIG. 3. In the cooling modethe evaporator instead of the thermal barrier 3 is connected to thevacuum side of the vapor jet compressor pump 22.

When available solar energy is not adequate for supplying heating orcooling needs, the thermal barrier solar collector 1, vapor jetcompressor pump 22, auxiliary energy supply 28 and separately energizedpump 27 may be combined. For heating purposes, vapor is generated ineither the auxiliary supply 28 or the motive steam generator portion 9of the solar collector 1 or by both in parallel to motivate the vaporjet compressor pump 22. The vapor jet compressor pump 22 in turn pumpsheat from the thermal barrier 3 of the thermal barrier solarcollector 1. The vapor condenser in the vapor jet compressor pump,provides pumping energy, heats the heat transfer medium which isdischarged from the vapor jet compressor pump 22 into the suction sideof the separately energized pump 27. The pump 27 controls the flow ofthe heat transfer medium, and ensures start-up, and flow stability. Ifthe vapor jet compressor pump 22 provides adequate circulation for theheating or cooling demand, the pump 27 is stopped by suitable controlsand the check valve G, and opens to permit by-pass flow from the vaporjet compressor pump around the pump. The discharge from the pump 27 orvapor jet compressor pump 22 enters the discharge heat exchanger 15where the heat transfer medium is cooled and returned again to the vaporjet compressor pump 22 to complete the cycle.

In the cooling mode of operation, the evaporator instead of the thermalbarrier 3, is connected to the vacuum side of the vapor jet compressorpump 22.

Although the invention has been described in terms of specificembodiments and applications, one of ordinary skill in the art, in lightof this teaching, can generate additional embodiments and modificationswithout departing from the spirit of the invention. Accordingly, it isto be understood that the descriptions and illustrations herein areproffered to facilitate comprehension of the invention and should not betaken to limit the scope thereof.

What is claimed is:
 1. A method for using solar energy to heat space,comprising the steps of:(a) collecting solar energy in ahigh-temperature vapor and a low-temperature vapor; (b) expanding thehigh-temperature vapor in a first vapor jet compressor pump; (c)compressing and condensing the low-temperature vapor in a second vaporjet compressor pump; and (d) passing at least some discharge from atleast one of said vapor jet compressor pumps through a discharge heatexchanger disposed within a heat transfer loop.
 2. The method of claim 1wherein the first vapor jet compressor pump and the second vapor jetcompressor pump are the same vapor jet compressor pump.